挥发性液体可否形成雾的探究

利用实验、文献对挥发性液体形成雾的条件进行了探究。结果显示,挥发性液体形成雾需要的条件为湿空气环境,溶液浓度大,挥发性强,挥发出的气体易溶于水,溶于水后的生成物易电离,形成的水合物能与水分子作用凝结成的粒子线性大小在10-3~10-7cm。     

辐射雾对激光吸收特性的研究

为了得到辐射雾对激光的吸收特性,本文根据Maxwell-Garnett公式计算了高频条件下辐射雾中等效介电常数,然后由等效介电常数得到激光在雾中的吸收率,最后通过MATLAB平台进行数值模拟得出了直观的结果。结果表明,辐射雾对激光的吸收率与辐射雾中等效介电常数的虚部有关,且与其虚部成正比关系;辐射雾对激光的吸收率与辐射雾的可见度成正比;随着频率的增加,辐射雾对激光的吸收率迅速增大,在5THz时达到最大值,随后逐渐减小,最后趋于一个稳定值。     

透雾连续变焦光学系统的设计

针对透雾连续变焦光学系统的特点,介绍了一种大口径、长焦距、透雾连续变焦光学系统的结构形式选择、系统中各组分相对孔径及初始结构的选取、像差平衡的方法.运用该方法设计的应用于某光电探测设备可见光通道的透雾连续变焦光学系统具有像质好、结构合理、加工装调的工艺性好等优点.     

Characterization of military fog oil by comprehensive two-dimensional gas chromatography

The most commonly used military fog oil is characterized by comprehensive two-dimensional gas chromatography (GC×GC) coupled to either Flame Ionization Detection (FID) or Time-of-Flight Mass Spectrometric Detection (TOFMS) to advance the knowledge regarding the complete chemical makeup of this complex matrix. Two different GC×GC column sets were investigated, one employing a non-polar column combined with a shape selective column and the other an inverse column set (medium-polar/non-polar). The inverse set maximizes the use of the two-dimensional separation space and segregates aliphatic from aromatic fractions. The shape selective column best separates individual polycyclic aromatic hydrocarbons (PAHs) from the bulk oil. The results reveal that fog oil (FO) is composed mainly of aliphatic compounds ranging from C₁₀ to C₃₀, where naphthenes comprise the major fraction. Although many different species of aromatics are present, they constitute only a minor fraction in this oil, and no conjugated PAHs are found. The composition of chemically similar aliphatic constituents limits the analytical power of silica gel fractionation and GC–MS analysis to characterize FO. Among the aliphatic compounds identified are alkanes, cyclohexanes, hexahydroindanes, decalins, adamantanes, and bicyclohexane. The aromatic fraction is composed of alkylbenzene compounds, indanes, tetrahydronaphthalenes, partially hydrogenated PAHs, biphenyls, dibenzofurans and dibenzothiophenes. This work represents the best characterization of military fog oil to date. As the characterization process shows, information on such complex samples can only be parsed using a combination of sample preprocessing steps, multiple detection schemes, and an intelligent selection of column chemistries.     

Investigation on RAFT Polymerization of a Y‐Shaped Amphiphilic Fluorinated Monomer and Anti‐Fog and Oil‐Repellent Properties of the Polymers

A Y‐shaped amphiphilic fluorinated monomer, 1‐(1H,1H,2H,2H‐perfluorodecyloxy)‐3‐(3,6,9‐trioxadecyloxy)‐propan‐2‐yl acrylate has been synthesized and its polymerization by reversible addition–fragmentation chain transfer (RAFT) homopolymerization has been investigated. The results show that the molecular weights of the polymers are controlled and all the molecular weight distributions are lower than 1.4. Well‐defined copolymers with 2‐(N,N‐dimethylamino)ethyl methacrylate have been prepared by RAFT polymerization, and the surface properties of the block and random copolymers have been examined by contact angle measurement for water and hexadecane. It has been found that the surfaces of the block copolymers simultaneously exhibit excellent anti‐fog and oil‐repellent properties.

     

基于FPGA的近红外实时透雾成像方法

针对雾天图像的退化现象,提出采用近红外波段成像和视频图像处理技术相结合的透雾成像方法。根据视频图像相邻两场直方图相似性特点,提出了改进的直方图均衡化算法处理雾天降质图像。改进算法简化系统结构,降低逻辑设计复杂度,节约了高速存储器部分硬件资源。算法经过MATLAB仿真验证,并在FPGA视频图像处理平台上硬件实现。实验证明改进算法增强雾天图像的同时满足标准视频图像处理25帧/秒的实时性要求,结合近红外波段透雾能力使雾天能见距离提高1.5倍以上。     

与雾霾相关的物理化学现象辨析

近几年雾霾频发,国内外有关雾霾的研究大量涌现,但相关研究主要集中在雾霾的组成、来源以及导致雾霾增强的气象条件及其变化规律等,很少采用物理化学原理进行讨论。作为气溶胶,雾霾涉及沉降与沉降平衡、表面吸附、扩散等诸多物理化学过程。通过构建简化模型并借助物理化学原理,本文对雾霾粒子的沉降与平衡、高度分布、雾与霾的区别、消除雾霾的方法等进行了讨论,得出了一些具有理论意义和应用价值的结论。     

光生电子和由还原剂提供的电子在卤化银颗粒中性能的比较

本文研究了光生电子和还原剂提供的电子在卤化银晶体中的行为。光灰化和还原剂灰化生成的灰雾中心的位置不同。光灰化时灰雾中心优先在卤化银颗粒内部形成,表明光生电子可以直接进入卤化银晶体的导带。还原灰化时内部灰雾中心只有在灰化剂量足够多时才形成,而且滞后于表面灰雾中心的形成,表明还原剂提供的电子虽然可以进入卤化银的导带,但它们进入导带的方式与光生电子不同。     

卤化银微晶体灰雾显影的研究

本文研究了卤化银乳剂经硫、金化学敏化后在D-19b和CD-4为显影剂的显影液中的灰雾显影。实验结果表明,经硫、金敏化的乳剂在D-19b显影液中灰雾显影所产生的密度均比在CD-4显影液中灰雾显影所产生的密度大。在D-19b显影液中一些硫敏化乳剂比金敏化乳剂灰雾显影密度大,但这些硫敏化乳剂在CD-4显影液中的灰雾显影密度却比同一金敏化乳剂的灰雾显影密度小。这些实验结果与硫、金敏化的两种乳剂分别在D-19b和CD-4显影液中灰雾显影动力学研究的结果完全一致。灰雾显影动力学的实验结果指出,硫、金化学敏化在D-19b和CD-4显影液的灰雾显影中对灰雾形成的影响有显著的区别。在D-19b显影液中硫敏化乳剂比金敏化乳剂灰雾显影的速度常数大,活化能低,而在CD-4显影液中则相反,硫敏化乳剂比金敏化乳剂灰雾显影的速度常数小、活化能高。     

地面目标动态红外特征模拟与隐身技术的研究

针对易受敌方红外制导武器攻击的地面军事目标,模拟并计算出其红外辐射特征。通过合理的假设,将复杂的三维辐射与对流耦合传热问题简化为一维瞬态传热问题,运用多层有限差分的数值计算方法计算模拟出目标瞬时温度变化方向图,得出其动态红外特征。在此基础之上,分别研究了地面目标不同部位(顶部与侧面)隐身所需要的表面发射率与温差的关系。分析了在不同温差条件下目标隐身所需表面发射率随时间的变化关系。计算模拟得出目标与背景在一日之中都存在明显的温差,最大温差可达10℃左右。分析得出利用水雾隐身使目标与背景的温差控制在2℃以内可达到良好的隐身效果。